Chris has the pocket tilt/EQ assembled, connected attery and all he heard was clicking from earphones.
After checking circuit over we found that the power supply pins on the opa4134 were etched backwards. cut and switched some traces around, applied power and a pop occured.
The 551 used on the power supply got warm.
We have a short somewhere as the batteries were getting warm, the 15v across the supply was now around 3v.
Is it possable for the 4134 to survive having the power supply pins backwards?
going to hook batteries directly to board less the 551.
the 2 opa 551's were correct.
All is SMD.
see pic of schematic
if all was not smd then I would just repair board andf get on with it.
hopfully the opamps (4134 and the 2-0pa551's are still good)
I think the OPA4134 opamps are destroyed by having their power polarities reversed.
The FETs "reduce" the 0.00008% distortion of the opamps only if they are connected to the negative supply, not when they are connected to ground. Remove them. Then the OPA551 opamps are not needed.
I forgot to remove from schematic.
will post updated schematic w/ power supply included.
Going to redesign the pcboard for one sided using TL074 dip op amps.